Draft means for fuel stokers



p 1934- E. J. SIMONS DRAFT MEANS FQR FUEL STOKERS Filed Dec. 6. 1952 3mm [mesz Jim 26 Patented Sept. '25, 1934 UNITED. STAT ES PATENT OFFICE 1,974,415 DRAFT MEANS FOR FUEL s'romms Ernest J. Simons, Spokane, Wash, assignor to General Machinery Company, Spokane, Wash.

Application December 6, 1932, Serial No. 645,873

2 Claims. (01. 110-45) My invention relates to draft means for fuel stokers and certain objects of the invention are to provide means for preventing all products of combustion from backing up from the burner retort through the stoker and. into the room wherein the l5 tinuous suction do not escape and that it is exjects are accomplished by devices illustrated in the accompanying drawing; wherein: Figure 1 is a general view in perspective showing my device attached to the domestic form of furnace stoker the fuel hopper of which has. a closed top;

'1 Fig. 2 is a view in slanting section through the hopper and draft connecting conduit; Fig. 3 is a view in side elevation showing the air entry valve for .the upper portion of the fuel hopper; Fig. 4 is a view in vertical section taken on a broken line 44 of Fig. 3. I

Referring to the drawing throughout which like reference numerals indicated like parts, the numeral 5 designates a burner retort such as used in connection with fuel stokers wherein draft is supplied to the lower portion of the retort through a main air conduit 6 by means of a fan '1 mounted within a casing 8 at the remote end of the main conduit which fan is driven by a motor 9. The fan and motor are mounted on the rear end of the usual fuel supply hopper 10 whose bottom portion has a tube 11 extending therefrom to a connection with the lower portion of the burner retort 5, and a worm conveyor 12 is mounted therein and extends from within the bottom of the hopper into the bottom of the retort. Said worm is rotated by the motor and by means of any suitable connection therewith as is well understood.

In the embodiment of my invention, as disclosed in Figs. 1 to 4 of the drawing wherein the. fuel 55 hopper 10 has a closed top and lid 13, I connect the upper portion of said hopper with the fan casing 8 by means of a suction tube 14. Said fan casing being'entirely closed with the exception of its connection with said tube and with the main air conduit 6, it will be obvious that all the air draft supplied to the burner retort 5 is drawn from the upper closed portion or crown of the hopper.

This is a very important feature of the invention for the reason that it. eliminates smoke and gas from backing up from the burner retort 5 through the worm conveyor tube 11 into the hopper 10 and out into the furnace room. Furthermore this feature, in addition to all such products of combustion from the retort back into the retort, also conveys all gas and other vapors arising from the fuel itself into the retort thus adding fuel to the fire and preventing the gases from eating into the interior surface of the hopper.

The suction tube 14 is provided with a damper I 15 whereby the down draft from the hopper 10 to the fan casing 8 may be regulated. It being understood that all air supplied'to the fan '7 and retort 5 must pass through the hopper and this being a large volume of continually flowing air, means must be provided for outside air to enter the hopper. This means is supplied by an air entry valve disposed in the upper portion of the hopper opposite to the point of the connection of the suction tube 14 therewith. As most clear-. ly shown in Fig. 4 of the drawing, said air entry valve consists of a casing 16 mounted in any desired manner in an opening through the hopper.

The open inner end of said casing is provided with a screen 1'1 and a flap door 18 pivoted at 19 serves normally as a closure for the open outer end of said valve casing. When the fan is not running the flap door drops to the full line closed position thus preventing escape of any gas through the valve casing, and when the fan rotates and causes a suction whereby the door is swung inwardly to the raised dotted position allowing air to freely enter. In Fig. 2 the arrows shown in full. lines designate the air passing through the hopper and picking up the gases from the retort and from the fuel which gases are destion, what I claim and desire to secure by Letters Patent of the United States is:---

1. In a draft means for the type of fuel stoker which consists of a burner retort, a fuel hopper having a closed top, a worm conveyor mounted within a tube extending from the hopper to the burner retort, a motored fan within a closed casing, and a main air conduit extending from a connection with the fan casing to a connection with the burner retort, the combination of a tube extending from a connection with the upper portion of the hopper at a point above the top of the normal fuel level within the hopper to a connection with the closed fan casing and forming the only inlet to said fan casing, and entry means for admitting air into the hopper consisting of a flap valve installed in the upper portion of the hopper above the top of the normal fuel level whereby rotary movement of the fan causes outside air to be sucked through the top portion of the hopper and the tube and projected into the burner retort.

2. In a draft means for the type of fuel stoker which consists of a. burner retort, a fuel hopper having a closed top, a worm conveyor mounted within a tube extending from the hopper to the burner retort, a motored fan within a closed casing, and a main air conduit extending from a connection with the fan casing to a connection with the burner retort, the combination of a tube extending from a connection with the upper portion of the hopper at a point above the top of the normal fuel level within the hopperto a connection with the fan casing and forming the only inlet to said fan casing, a damper installed in said tube, an air entry valve installed in the upper portion of the hopper directly opposite to and on a level 'with the aforesaid tube connection, and a flap door pivotally mounted within the valve whereby rotary motion of the fan causes said door to swing inwardly and whereby outside air is drawn in and across the top portion of the hopper above the normal fuel level therein.

- ERNEST J. SIMONS. 

